Structural tower



April 7, 1925. 1,532,410

R. KAGIWADA S TRUCTURAL TOWE R Filed April 25. 1923 2 SheecsShee 1 April 7, 1925. 1,532,40

R. KAGIWADA l STRUCTURAL TOWER Filed April 25. 1923 2 Sheets-Sheet 2 31400411( of, Wzffsiw:

e have invented aerea am. a' tra naar.

razonar nneruann, or wnsnrnewon, :orsrnrcr or COLUMBIA.

App1ication1ed April, 1923. Serial Nl'o. 634,449.

of structural towers in general, particularly of that type of towers, wherein thestructure is normally subjected to a'constant strain of a given magnitude acting in a fixed direction, besides the rwind and other pressure caused-by the elements, as well as torsional moments of considerable magnitude.-

2@ members required According to the stand-ard practice, vit'has been customary to construct a tower of such description with a plurality of corner posts or colu'inns which constitute the principal of the total load on the structure.. But the imperfect features of such a construction are many, and have long been known to those whdare versed in the art.

The customary use, for instance, of the material of a uniform section in manufacturing the main columns makes it unavoidable, especially f' the case of high towers, that a larger pa t along its length should a@ possess a greater size, and consequently a greater weight, than what is actually required., This results from the 4necessity of manufacturing them of a large enough sec-.

tion to take care oil the maximum load the columns are designed to withstand. -Because the distributed load at any point in the greater part of its lengthis smaller than the maximum that acts on the smaller portion of its longitudinal dimension, it has been unavoidable that the greater length of such a column should have a larger size than the necessary strength demands.

Still another cause of the excessive weight of a long column is the dimensional allowance given to the material tused, which being done with a view of.. off-setting itsslenderl' ness that would result if the mathematical deductions were depended upon as a sole determinant of the ultimate size of its section. Such allowance or additional size would be totally unnecessary if it were possible tb use the materiak'having a proper size to correspond withthe actual require- .ment at each section or length of the column. But, heretofore, it has not been possible to to sustain a greater part do so in the face. of economic and other considerations that have to beconsidered.

Besides, the usual construction does not lend itself inavoiding the use of idle members v which function only when the strain` acts 1n a certain direction,v being absolutely useless and idle when the structure they compose is subjected to a strain in any other direction. Then, again, the secondary stresses which are statistically indeterminate,.form a feature which has always been present in the calculation of this type of structure, and. contributed in no small degree in Vcausing a measure of uncertainty to creep into the design ofya structural tower with respect to its ultimate strength, since more or less guess work had to be resorted to in thecalculations. Y l

Further, a tower of the type designed 'in accordance with the usual practice is far from being an ideal structure to 'withstand torsional moments, especially when they are applied with a suddenness that lowers the time,constant so greatly that the strain assumes an enormous magnitude. This feature in the customary design is a grave imperfection, particularly in the case. of towersv for electric transmission lines and forisimilar purposes, l g

rl`he essential object of my invention, therefore, is in providing a novel and edicient form of structural tower by adopting an improved construction, wherein the im-Y perfect features of the customary con struc.A tion reviewed in the foregoing paragraphs are'eliminated and at the 'same time, render both the design and construction greatly simple. .y

Other objects attained and superiority realized by my improved construction will be pointed out and particularly set forth in the claims..

. To 4these'ends, my invention comprises a an accuracy' heretofore unattained, and to l reduce the total weight of the structure toa minimum, whilevassuring a maximum ultimate strength with respect to the strain a tower of the type mentioned is expected to bear,

In carrying out invention, I construct the tower structure y mounting one upon another Yof a. plurality of constructional units formedby two sets of horizontal members, each set of which forms a polygon and joined with each other,` by a plurality of diagonal members. -V

These\polygons, which may, .or may not be of thr same size, as. desired, lie in two independent planes parallel to each other' j with a suitable distance between them. They yare, arranged .to have a common vertical axis, around which one has a lead of with respect to each other. In other words, their relative positions arou'nd the common vertical axis is such that if one ofthem should be` turned around, the axis through an angle of 45,"its vertical projection upon the plane of another polygon will,'in case they are of the same size, form a congruent figure 4with the other; and that when the polygons are4 of diii'erent sizes, the said projection will form a polygon whose sides are parallel with those of the other.

By reason ofthe construction above described, it will be clearly seen that an apex of one polygon will be equidistant from the o a xes of the other polygons rvon either si e o `the former., Hence, all the diagonal meid bersjoining-the apexes of one polygon with those of the second polygon will be, of the same lengths, regardless of the number of u sides 1n the polygon; and the resultant structure will present a form of polyhedron, bounded by a luralvity of unlform sized lateral planes. his ol hedron constitutes what I term throughout this specification the constructional-unit of my presgnt invention.

In the drawings, like numerals of reference indicate similar parts in the several views, and wherein:

Figure 1 isa diagrammatic front elevation of one form of thetower, embodying mdnvention.' vf p igure 2 is a horizontal plan of the lower end thereof. V I

Figure 2 is'. an enlarged fragmentary elevation of the tower, showing one means 1of- ,joining the structural( units. 4,

Figure 4 is a view somewhat similar to Figure 3, showing a slight modi-fied form of means for .connecting the adjacentstructural elements com` rising the tower.

Iigure 5 is'za side elevation of Figure 3, an l.

Figure 6 is a plan view ofaj gusset plate that may be employedin Vthe joining of the structural elements, 'v

In the case of the' specific forms shown as ali-illustration of -my v improved construction 'and depicted in the accompanying drawings, the polygons are in the form of equilateral squares, such .as e--f-g-h, and

la tower of any l in design.

fZ-j--z-J, Figure 2, corr-.posed of horizontal members, al, d a', and al, and c, c, c, and c, respectively, Figure l; thesesquares being joined at their apexes by diagonal members m, n, p, and g, etc., of a uniform length, in Such a Way that the two squares are 45 apart from each other around the common axis. In this instance, my constructional nnit presents the form of a decahedron.

By mounting a required,l number of these units one' above the,d other, any desired height of a tower may be attained. Also, by proporticningthe size of the respective squares, the unit may be made to produce any required taper of the tower desired; or, on the contrary, it may be made to form no taper, so that the diagonale may lie in their squares. p invention provi es a' construction whereby desired height and shape may be formed.

In the ordinary construction, the diagonale or braces playrno part in offering resistance to wind pressure or other forces. In such cases, these members simply add to the weight of the tower, without in any way contributing-to its strength. But in my` improved construction, the-use of such idle members has been totally avoided, and the constituent members are so arranged and disposed that each piece is effective atall times. yihe elimination of the idle` Amembers, a considerable vreduction is effected in the total weight ofthe tower. Furthermore, in my improved construclrespective lane, perpendicular to that of the t will; therefore, beseen that my tion, the unit decahedron, in the specific form illustrated, and the polyhedron, covering -all,cases, being always composed of triangular formations','the, statistically in determinate features arel entirely absent, re-

sultng in greater accuracy and certainty By discarding ythe customary form of main columns and substituting therefor a series of diagonale of the size properly proportioned to possess the strength required at each stage, the calculations of,

the structure is not only'reduced to a great simplicity, but it can. be made to faithfully conform with both thetheoretical and practical requirements.

It will also be clearto anyone versed in the art that the novel formation in my constructlon, gives the structure a resistance to twisting moments, fargreater than would be possible in the customary design This is anespecially important lconsideration in such towers as are intended to support electric transmission lines, or wireless antenna conductors, and in similar towers, since the strain produced 1n a `tower 1s sudden, and, inmost cases, complex, as

when a breakage occursin one or more of the conductors it carries. l Y A modified from'of jint adapted to effeet economy in the cost of manufacture of a4 tower is shown in Figures 3 and 5. In the form shown, the bending of the materials is made unnecessary, the members being joined by the use of gusset plates 5 and 5 in Figure 3, and 5a and 5'b in Figure 5, as shown. These figures also indicate how, by properly proportioning the length of the, sides Z d, c, 0, etc., of the squares in the decahedron unit, the diagonals, p, p, etc., may be causedto lie in a plane perpendicular to that of the square.

In Figure 4, the diagonals are shown as being` secured to the horizontal members d and '0,' through the medium o gumet lates 6, shown more clearly in Figure 6, 1t being of course understoody that these plates necessarily have to be slightly curved to engage around the apex of the polygons formed by said horizontal members d and c.

Various modifications may be introduced in the construction to meet specific requirements, Without deviating from the spirit of my invention, and I, therefore, desire that the particular forms shown in the accompanying drawings shall A not be construed to limit the scope of my invention in any Way whatsoever.

Having thus described my invention,

what I claim as new, and desire to secure by Letters-Patent, is:

1. In a structural tower, the construction unit, consisting of a polygon composed of a set of horizontal members, a second polygon composed of a, second set of horizontal members, vthe said pair of polygons being parallel to each other, and having a common axis, around which oneof the polygons is disposed in respect to the other with a lead equivalent to one-half the angle subtended by the apex of said polygons, in combination with a plurality of diagonal members joining the said pair of polygons at their respective apexes and forming a plurality of triangles with the horizontal members of the polygons, substantially as and for the purpose described.

2. A structural 'tower composed of a plurality of the constructional units set forth' in the claimy 1, the said units being mounted one upon another, the horizontal members composing the polygons of each adjacent unit being common to each other, substantially as and for the purpose set forth.

In testimony whereof I ax my signature.

RYGHEI KAGIWADA. 

